[Value of 68Ga-DOTA-TATE Positron Emission Tomography/Computed Tomography in the Localization of Culprit Tumors Causing Osteomalacia with Negative 99mTc-HYNIC-TOC Single Photo Emission Computed Tomography].

Objective To analyze 68Ga-DOTA-TATE positron emission tomography/computed tomography (PET/CT) imaging features of tumor-indud osteomalacia (TIO) patients with negative 99mTc-HYNIC-TOC single photo emission computed tomography (SPECT) findings and to investigate the value of 68Ga-DOTA-TATE PET/CT in accurate localization of culprit tumors.Methods We retrospectively analyzed 68Ga-DOTA-TATE PET/CT imaging features including location,size,density,the maximum and mean standardized uptake value in 37 TIO patients with negative 99mTc-HYNIC-TOC SPECT findings.Results Totally 37 solitary TIO tumors,including 35 phosphaturic mesenchymal tumors and 2 spindle cell tumors confirmed by pathological examinations,were detected via 68Ga-DOTA-TATE PET/CT scans in the included 37 cases. These 37 TIO tumors showed obviously increased activities,with an maximum standardized uptake value of 7.2±4.3 and mean standardized uptake value of 4.3±2.4. The average maximum diameter was (1.9±0.7) cm. The majority of the tumors occurred in the lower extremities (19/37),followed by the trunk (11/37),maxillary/mandibular bone (5/37),and upper extremities (2/37). In addition,24 bone lesions were located in long bones of lower extremities (13/24),most of which demonstrated eccentric growth (8/13). Osteolytic changes (14/24) were observed mainly in the lesions via the corresponding CT imaging;meanwhile,sclerotic changes presented in nine cases. Of the 13 soft-tissue lesions,the majority (10/13) showed well-circumscribed isodense or hypodense nodules on the CT images,with spot calcification in one lesion located in the pleura.Conclusions 68Ga-DOTA-TATE PET/CT scans can detect the TIO culprit tumors miss-diagnosed by 99mTc-HYNIC-TOC SPECT. Somatostatin-receptors highly expressed lesions with focal osteolytic or osteosclerotic change in bone and isodense or hypodense nodules in soft tissue will favor the diagnosis of TIO tumors.